Chapter 2 - The Key Principles of Economics - Exercises - 2.4 The Principle of Diminishing Returns - Page 46: 4.1

300 pages

The law of diminishing returns tells us that, unless other inputs are increased, continuing to increase a single input will give a lower marginal increase in output. Since the last worker hired resulted in 300 pages of additional output, adding another worker would result in a lower marginal increase, so less than 300 additional pages would be output.